That finding, from a new report on perceptions of military benefits to be released Thursday, is proof of a long-held belief among military personnel planners that troops prefer cash now rather than later, said author Todd Harrison of the Center for Strategic and Budgetary Assessments, an independent think tank.

The Pentagon could save money and improve the perceived value of its compensation package by making that trade-off, said Harrison, whose report looks at the value service members and retirees place on benefits.

Service members up to age 29 said they could accept waiting until age 50 for retired pay if they received as little as $250 more a year in pay. Those aged 30 to 39 would want about $520 more a year, while those 40 and older put the figure at $650 or more a year.

The average age to begin drawing retirement pay is 47 for officers and 43 for enlisted members, Harrison said, so waiting until age 50 to draw the pay would put a bigger hit on enlisted members.

But for both officers and enlisted troops, the hit would be huge. An O-6 who retired today at age 47 with 25 years of service would give up almost $190,000 over three lost years of retirement pay. An E-8 who retired today at age 43 with 25 years of service would give up almost $277,000 over seven lost years of retirement pay.

Those figures factor in an average annual cost-of-living adjustment of 2.5 percent.

In contrast, an immediate 1 percent raise would amount to annual totals of just $612 for the E-8 and $1,188 for the O-6.

Harrison said it's possible that some people might try to stay in service longer if retired pay didn't start immediately at retirement, in order to boost their eventual retirement pay.

Harrison's survey found service members of all ages prefer the current retirement system, which requires at least 20 years of service for full retirement benefits, over shorter and longer alternatives, including a 15-year model that would be more generous for troops and costlier to the government.

But even younger members slightly favored 20-year retirement over a 15-year plan, according to the survey of more than 2,600 service members and 723 retirees.

"The data suggest that the years of service required for retirement should not be reduced because it would both cost more and have a negative impact on the way the majority of service members in all age groups value their compensation," Harrison's report says.

Harrison's full report will be released Thursday at the National Press Club in Washington, D.C. The event is open to the public, but reservations are required. To make a reservation, send an email to rsvp@csbaonline.org.